Elizabeth Noble enjoyed a full and active life, and is nobody’s fool. For more than a quarter-century, she taught statistics in the School of Education at the University of Missouri-Kansas City. In retirement, she continued to work as a consultant, and travelled widely in Europe and Asia.

When Noble was diagnosed with Age-Related Macular Degeneration, which slowly blurs the sharp central vision that we rely on to read, drive, and identify faces, she wanted to do something about it. And she thought she had found an answer — a research study described on ClinicalTrials.gov, a website run by the National Institutes of Health (NIH), the US government’s premier biomedical research agency.

It seemed scientifically legitimate, so in June 2015 Noble went to a clinic in Sunrise, Florida, where staff sucked a small quantity of fat from around her belly button, treated it with enzymes to extract the cells it contained, and mixed those cells with a sample of Noble’s blood plasma. They injected the mixture into Noble’s eyeballs, charged her $5,000, and told her to avoid strenuous activity for the next three days.

Three days later, when the 72-year-old was seen by doctors at the University of Miami’s Bascom Palmer Eye Institute, strenuous activity was out of the question. Noble’s eyes hurt and she was nauseous. Her retinas were bleeding and she could just make out a hand being waved in front of her face.

Noble’s sight continued to deteriorate and one year later she couldn’t tell the difference between night and day. “That’s as bad as it gets,” Thomas Albini, an ophthalmologist at the Bascom Palmer Eye Institute, told BuzzFeed News, describing the condition of the woman he identified only as Patient 1.

In the latest issue of the New England Journal of Medicine, Albini and his colleagues describe the cases of three women treated by the same stem cell company, each of whom became legally blind. The doctors don’t name the women involved, but BuzzFeed News established the identities of two of them from courtfilings and other public documents.

This isn’t the first time that people have been harmed by clinics offering unproven treatments purportedly involving stem cells. In 2010, for example, a woman with the autoimmune disease lupus died after her own bone marrow cells were injected into her kidneys at a clinic in Thailand. And in 2013, the Florida Department of Health revoked the medical license of Zannos Grekos over the death of a 69-year-old woman. He had extracted material from her bone marrow, filtered it, and then infused it into the arteries feeding her brain. The woman had a stroke, and died shortly afterwards.

But the latest tragic cautionary tale has a disturbing twist, as two of the women who were blinded contacted the company involved, now called US Stem Cells but formerly known as Bioheart, only after reading about its macular degeneration study on ClinicalTrials.gov.

The site was launched in 2000 after Congress passed a law demanding that the NIH keep a registry of clinical trials — experiments with new drugs on volunteer patients — so that drug companies couldn’t sweep negative results under the carpet. ClinicalTrials.gov has since grown to include some 290,000 studies run in countries across the globe.

But with only minimal screening of the listings, experts who track the burgeoning and loosely regulated landscape of stem cell clinics fear that the website is being abused to claim spurious legitimacy for unproven therapies that are being sold for profit.

“It’s very easy to register studies on ClinicalTrials.gov and essentially use a government website as a marketing device,” Leigh Turner, a bioethicist at the University of Minnesota, told BuzzFeed News.

Noble told the doctors at the Bascom Palmer Eye Institute that she thought her treatment was part of a clinical trial. Patients are not usually charged to take part in research. Yet each of the three women described in the case reports were charged $5,000, and Albini said that the consent paperwork made no mention of a study.

“I think it was presented as a clinical trial and documented as a fee-for-service procedure,” Albini said. In September 2015, shortly after the three women were treated, the ClinicalTrials.gov listing was amended to say the study had been “withdrawn prior to enrollment.”

Before that change was made, it is easy to see why Noble and Patsy Bade, who also decided to seek treatment after finding the ClinicalTrials.gov listing, might have found it convincing. It includes an long list of conditions that could exclude people from participating, and indicates that patients would be studied 6 months after their treatment, to record their field of view and the sharpness of their vision.

Neither Noble nor Bade had severe sight loss before their eyeballs were injected with material extracted from their abdominal fat. Noble still had 20/30 vision in her left eye, which is barely different from normal. “It’s good enough to read newspaper print,” Albini said. “It’s very functional vision.” Bade, who was 78 when she was treated and lives in Venice, Florida, struggled to read fine print and had problems driving at night. But otherwise, she could function normally.

The back of Patsy Bade’s left eye after the stem cell treatment. Dark patches show bleeding in the retina.

“These ladies who were both independent were rendered blind,” their attorney, Andrew Yaffa of Grossman Roth Yaffa Cohen in Coral Gables, Florida, told BuzzFeed News. The women sued US Stem Cell, the affiliated US Stem Cell Clinic, and two medical professionals who were involved in the procedures.

The suits were settled for undisclosed sums, with a confidentiality agreement that prevents Yaffa from naming the women or the company involved. Noble and Bade also told BuzzFeed News that they were not allowed to discuss their cases.

“This litigation has been resolved to the mutual satisfaction of the parties,” Yaffa said.

A couple of days after her injections, Bade turned up at the Bascom Palmer Eye Institute with bleeding retinas. Again, her eyesight rapidly deteriorated. A year later, she could just detect a hand waving in front of her face with her right eye, and had 20/200 vision in her left. That is the legal threshold for blindness, and means she could read an eye chart at 20 feet only as well as a person with normal vision standing 200 feet away.

Both women’s eyesight would likely still be fairly good had they not been given the injections. Macular degeneration typically proceeds “pretty slowly,” Albini said.

Neither Mike Tomás, US Stem Cell’s CEO, nor Kristin Comella, the company’s chief science officer, returned emails and phone calls from BuzzFeed News. Comella is described on the company’s website as a “world renowned expert on regenerative medicine.” She is not a medical doctor, and is enrolled as a PhD student in biomedical engineering at Florida International University in Miami.

The company responded instead with a statement from its PR firm, Becker Public Relations, which said: “Since 2001, our clinics have successfully conducted more than 7,000 stem cell procedures with less than 0.01% adverse reactions reported. We are unable to comment further on specific cases due to patient confidentiality or legal confidentiality obligations. Neither US Stem Cell nor US Stem Cell Clinic currently treats eye patients.”

On its website, US Stem Cell Clinic says it offers treatments for conditions from Parkinson’s disease to congestive heart failure. US Stem Cell’s PR company would not say how many of the 7,000 procedures the company claims to have performed involved patients with eye diseases.

While the blinding of three patients is an extreme example, experts who follow the stem cell industry worry that other people may have been harmed by clinics offering unproven treatments, without their cases coming to public attention.

“What I’m most worried about is that this may be the tip of the iceberg,” Paul Knoepfler, a stem cell biologist at the University of California, Davis, told Buzzfeed News. Last year, he and Turner of the University of Minnesota published a survey that identified 570 clinics offering unproven stem-cell treatments across the US.

Most of these clinics argue that their treatments do not need to be regulated by the Food and Drug Administration (FDA) because they are merely injecting people’s own stem cells back into their bodies. The FDA maintains that these cells count as drugs, which it must approve for clinical use, if they are more than “minimally manipulated” and are not replacing cells with the “same basic function.”

Last September, the FDA held a two-day hearing on treatments based on human cells. “The FDA is evaluating the feedback we received at the hearing, along with the written comments, as we work to finalize our guidance,” agency spokesperson Andrea Fischer told BuzzFeed News by email.

It’s unclear whether that will to lead to a crackdown on clinics offering unproven stem-cell treatments — especially as President Donald Trump’s nominee for FDA commissioner, Scott Gottlieb, in 2012 co-wrote an Op-Ed for the Wall Street Journal criticizing the agency’s efforts to regulate cells as drugs.

“The FDA is perennially complaining to Congress that it lacks the resources to do its day job of regulating products that fall squarely in its purview,” Gottlieb and his co-author wrote. “Yet in chorus, the agency is always seeking novel authority to insert itself into new areas of science where its mandate is shaky.”

Whatever the FDA does next, Turner argues that the NIH should do more to screen the listings posted on ClinicalTrials.gov.

“The information on ClinicalTrials.gov is provided by the study sponsor or principal investigator and posting on ClinicalTrials.gov does not necessarily reflect endorsement by the NIH,” Renate Myles, an NIH spokesperson, told BuzzFeed News by email.

Earlier today, the NIH added a similarly-worded disclaimer to the website. Myles said that the change was made because of the concerns raised by Alibini’s paper.

“It is time NIH representatives stopped giving boilerplate responses,” Turner said. “They should have addressed this problem before patients were harmed.”